/**
 * Software License, Version 1.0
 * 
 * Copyright 2003 The Trustees of Indiana University.  All rights reserved.
 * 
 *
 *Redistribution and use in source and binary forms, with or without 
 *modification, are permitted provided that the following conditions are met:
 *
 *1) All redistributions of source code must retain the above copyright notice,
 * the list of authors in the original source code, this list of conditions and
 * the disclaimer listed in this license;
 *2) All redistributions in binary form must reproduce the above copyright 
 * notice, this list of conditions and the disclaimer listed in this license in
 * the documentation and/or other materials provided with the distribution;
 *3) Any documentation included with all redistributions must include the 
 * following acknowledgement:
 *
 *"This product includes software developed by the Community Grids Lab. For 
 * further information contact the Community Grids Lab at 
 * http://communitygrids.iu.edu/."
 *
 * Alternatively, this acknowledgement may appear in the software itself, and 
 * wherever such third-party acknowledgments normally appear.
 * 
 *4) The name Indiana University or Community Grids Lab or NaradaBrokering, 
 * shall not be used to endorse or promote products derived from this software 
 * without prior written permission from Indiana University.  For written 
 * permission, please contact the Advanced Research and Technology Institute 
 * ("ARTI") at 351 West 10th Street, Indianapolis, Indiana 46202.
 *5) Products derived from this software may not be called NaradaBrokering, 
 * nor may Indiana University or Community Grids Lab or NaradaBrokering appear
 * in their name, without prior written permission of ARTI.
 * 
 *
 * Indiana University provides no reassurances that the source code provided 
 * does not infringe the patent or any other intellectual property rights of 
 * any other entity.  Indiana University disclaims any liability to any 
 * recipient for claims brought by any other entity based on infringement of 
 * intellectual property rights or otherwise.  
 *
 *LICENSEE UNDERSTANDS THAT SOFTWARE IS PROVIDED "AS IS" FOR WHICH NO 
 *WARRANTIES AS TO CAPABILITIES OR ACCURACY ARE MADE. INDIANA UNIVERSITY GIVES
 *NO WARRANTIES AND MAKES NO REPRESENTATION THAT SOFTWARE IS FREE OF 
 *INFRINGEMENT OF THIRD PARTY PATENT, COPYRIGHT, OR OTHER PROPRIETARY RIGHTS. 
 *INDIANA UNIVERSITY MAKES NO WARRANTIES THAT SOFTWARE IS FREE FROM "BUGS", 
 *"VIRUSES", "TROJAN HORSES", "TRAP DOORS", "WORMS", OR OTHER HARMFUL CODE.  
 *LICENSEE ASSUMES THE ENTIRE RISK AS TO THE PERFORMANCE OF SOFTWARE AND/OR 
 *ASSOCIATED MATERIALS, AND TO THE PERFORMANCE AND VALIDITY OF INFORMATION 
 *GENERATED USING SOFTWARE.
 */
package cgl.narada.protocol;

/**
 * The Connection Setup, specifies the transport protocol, and information
 * associated with the transport layer that are needed to effectively set up
 * a server node.
 *
 * @author Shrideep Pallickara
 * $Revision$
 * $Date$
 *  
 */

 
public class ConnectionSetup {
  private int transport;
  private int portNum;

  /** Creation of the Connection Setup, specifying the transport layer that
      needs to be employed and the portNum associated with the socket through
      which other nodes would communicate with the node in question */
  public ConnectionSetup(int transport, int portNum) {
    this.transport = transport;
    this.portNum = portNum;
  }
  
  /** This reflects an unmarshalling of the connection setup information 
      regarding a node that is received over a link 
      @param data - Representation of a connection as a sequence of bytes.
  */
  public ConnectionSetup(byte[] data) {
    transport = (int) data[1];
    portNum   = getValue(data[2], data[3]);
  }
  

  /** Returns the transport identifier associated with a certain connection 
      setup 
      @return The transport layer over which this connection setup 
      communicates.
  */
  public int getTransport() {
    return transport; 
  }

  /** Returns the port number associated with the socket used for communication
   */
  public int getPortNum() {
    return portNum;
  }
  
  private int getValue(byte a, byte b) {
    int x = a;
    int y = b; 
    /** The 8th-bit in the byte is 1, therefore it gets treated as as
	a -ve integer ... accomodate this case */
    if (x < 0)
      x += 256;
    if (y < 0)
      y += 256;
    return ((x << 8) + (y << 0));
  }
  
  /** A marshalling of the connection setup  information. The unmarshalling
      is achieved through one of the constructors in this class 
      @return A representation of the connection setup as a sequence of bytes.
  */
  public byte[] getBytes() {
    byte[] data = new byte[4];
    data[0] = Protocol.CONN_SETUP;
    data[1] = (byte) transport;
    data[2] = (byte) ((portNum >>> 8) & 0xFF);
    data[3] = (byte) ((portNum >>> 0) & 0xFF);
    return data;
  }
}

